Work = Force * Distance Work = 5 * 6 = 30 Foot Pounds

Work = Force * Distance

How much work in ft-pounds is done lifting a 25 pound ball 8 feet?

A spring of natural length Hooke’s Law F(x) = kx

Tom McLean hung his 54# back pack on the scale at the Appalachin Trail and the spring stretched ¾ of an inch. F(x) = kx 54 = 0.75k 216/3 = k #/in F(x) = 72 x

It takes Bruce McLean a force of 40 pounds to compress his garage door spring ¼ inch. F(x) = kx 40 = 0.25 k 160 = k #/in F(x) = 160x

If it takes 3 # to hold the spring two feet beyond its natural length F(x) = kx F(2) = k2 = 3 K = 3/2 thus F(x) = 3/2 x K = 3/2 thus F(x) = 3/2 x The spring constant is 1.5. The spring constant is 1.5.

How much work was done in pulling the first spring to two feet beyond its natural length? Work is the area of the green region.

F=20 # keeps a spring 4 feet beyond its natural length. Find k if F(x) = kx

With k=5, how much work if stretched from natural length to 6 feet beyond natural length? A.30 ft-lbs B.60 ft-lbs C.90 ft-lbs

How much work is done in pulling the first spring two additional feet? Work is the green area.

20# needed to stretch 4 ft. How much work to pull it another 4 ft?

Work = Force * Distance Force = 9.8 * 5 = 49 Newtons Work = 9.8 * 5 * 0.6 = 29.4 Newton-Meters (Joules)

Work = Force * Distance How much work is done if a force of 49 N is lifted 6 meters? W = 49 * 6 = 294 Joules

If it takes 3 N to hold the spring 1.8 meters beyond its natural length F(x) = kx F(1.8) = 1.8k = 3 K = 5/3 thus F(x) = 5/3 x K = 5/3 thus F(x) = 5/3 x The spring constant is 5/3. The spring constant is 5/3.

How much work is done in pulling that spring 1.8 additional meters? Work is the area that is green.

How much work is done in pulling that spring 1.8 additional meters?

If Tom’s pack weighed 54 – 0.01x and Tom weighed 160 – 0.01x + 200/x 1.1, how much work did he do in walking the 2178 miles? Trip starts at x=10 and finishes when x = 2188 miles.

Mile Pounds

4 N holds a spring 0.2 meters beyond its natural length. Find k in F = kx

Find the work in stretching that same spring from ½ meter to 1 meter

Find the work in emptying a swimming pool filled with water.  Thin slabs of water must be lifted x feet. Each slab weighs 62.43*20*40  x for 5’ 62.43*20*8*(10-x)  x (y-0)/(x-10)=40/-5

 The weight of one cubic foot of water is gallons per cubic foot times pounds per gallon, which equals pounds of water per cubic foot.

Find the work in emptying a swimming pool filled with water.  Thin slabs of water must be lifted x feet Each slab weighs 62.43*20*40  x for 5’ 62.43*20*8*(10-x)  x